Electrical storage devices such as lithium ion capacitors and lithium ion batteries advantageously have a high energy density, a low self-discharge rate, and good cycle performance. Therefore, in recent years, such storage devices have been expected to be used as a power source for automobiles such as hybrid vehicles and electric vehicles by increasing the size or the capacity of the storage devices. Some examples of the electrical storage devices used as power sources for automobiles are of a wound type in which a wound electrode group formed by winding positive and negative electrodes via a separator about an axial core is contained in a bottomed cylindrical container together with an electrolyte.
In the conventional electrical storage devices of this type, an insulating ring member is attached to the outer peripheral edge of the current collecting member on the side of a lid member for electrical insulation between a current collecting member and the container. Drawing is performed on a peripheral wall of the container at a location above the insulating ring member to form an annular projected portion such that an electrode group unit is fixed in the container by the annular projected portion and the insulating ring member (Patent Document 1).